1. Field of the Invention
The present invention relates to a grinding chip fitting type grinding plate suitable for grinding stones. More particularly, the present invention relates to an improvement of a grinding plate in which grinding chips each having a cylindrical mounting portion can be easily attached to and detached from the grinding plate.
2. Description of the Related Art
The assignee of the present invention disclosed a grinding chip fitting type grinding plate which achieves the same object as the present invention (see Japanese Utility Model Publication 58-15090). This grinding plate has a structure as shown in FIG. 1. That is, a plurality of chip receiving holes 3 are formed in the bottom surface of a base plate 2 having a rotation transmitting portion 1. The base portions of grinding chips 5 are fitted into the chip receiving holes 3 so that the grinding chips 5 are restricted in the rotational direction and the radial direction of the grinding plate. The base portion of each grinding chip 5 has a flange 4 with a tapered peripheral surface. Also, there is provided a holding plate 6. The holding plate 6 is provided with chip through holes 7 each having a tapered inner surface whose diameter is smaller than the diameter of the flange 4. The holding plate 6 is attached to the base plate 2 such that the grinding chips 5 enter the corresponding chip through holes 7 and the flanges 4 of the grinding chips 5 engage with the inner tapered surfaces of the chip through holes 7. The holding plate 6 is secured to the base plate 2 with a plurality of bolts 8 so that the grinding chips 5 are restricted in the axial direction.
The above-described grinding plate has many advantages as follows.
(a) Since movement of the grinding chips 5 in the rotational and radial directions of the grinding plate is restricted by the base plate 2, and movement of the grinding chips 5 in the axial direction is restricted by the holding plate 6. Accordingly, even when the grinding chips receive a lateral thrust or a shock from the surface of a stone during a grinding operation, the thrust or shock is resisted by the stiff base plate 2. Therefore, the weight of the holding plate 6 can be decreased, and the number of the bolts 8 for fastening the holding plate 6 can be decreased. In addition, the work for attaching or removing the grinding chips 5 can be simplified. PA1 (b) The grinding chips 5 whose base portions are fitted into the receiving holes 3 of the base plate 2 are held together by the holding plate 6 for fixation. Therefore, when the grinding chips 5 are to be replaced with new grinding chips, they are easily removed from the base plate 2 by disassembling the holding plate 6. PA1 (c) Since lateral thrust and shocks acting on the grinding chips 5 can be resisted by the strong base plate 2, there is some very play produced between the grinding chips 5 and the base plate 2. Even when play is produced, the grinding chips do not come off insofar as the holding plate 6 does not fall down. Therefore, the grinding plate is very safe. PA1 (d) Once a user buys the base plate 2 and the holding plate 6 as a set, it is necessary for the user to buy only the grinding chips 5 even when grinding performance deteriorates. Accordingly, operational costs can be decreased. PA1 (e) When the grinding chips 5 have worn unevenly, they can easily be exchanged. Also, the layout (positions) of the grinding chips 5 can be changed. PA1 (f) When part of the grinding chips 5 are damaged, the grinding plate can easily be repaired by replacing the damaged grinding chips with new ones. PA1 (g) The grinding chips 5 can be formed simultaneously using a die, and the base 2 and the holding plate 6 have simple structures. Therefore, manufacturing costs can be decreased. PA1 (h) A manufacturer or dealer is required to send to a user only grinding chips. Transportation and packaging become simpler.